1. Field
One feature generally relates to wireless communications, and more particularly, to methods and devices that retransmit information due to reception of erroneous information.
2. Background
The increased availability of Wireless Local Area Networks (WLANs) has allowed stations, such as desktop computers, laptop computers, hand held personal digital assistants (PDAs), and mobile phones, to wirelessly connect with one another through a variety of networks, such as Local Area Networks (LANs) and the Internet, to transfer data between them. For example, a user can take a laptop computer from a desk into a conference room to attend a meeting and still have access to a local network to retrieve data and have access to the Internet via one or more modems or gateways present on the local network without being tethered by a wired connection.
A WLAN may be comprised of four primary components. These components may include stations (STAs), one or more access points (APs), a wireless medium and a distribution system. The network is built to transfer data between stations that may include computing devices with wireless network interfaces. For example, laptop computers, desktop computers, mobile phones, and other electronic devices having wireless network interfaces are examples of stations within a network. Access points are devices that allow stations to connect to one another and transfer data. Examples of access points include routers, centralized controllers, base stations, and site controllers.
Data is transmitted over a WLAN via packets. Packets contain control information and payload information (e.g., the data); the form of packets vary depending on the communication protocol. A station may desire to transfer multimedia content, such as video, over the WLAN to another station via one or more access points.
In wireless (radio) communications, Multiple-Input and Multiple-Output (MIMO) offers significant increases in data throughput with little to no additional bandwidth or transmit power. This is achieved this by higher spectral efficiency (i.e., more bits per second per hertz of bandwidth) and link reliability or diversity (e.g., reduced fading). Multi-User (MU)-MIMO permits a network device (access node) to communicate with multiple client stations at each transmission window, by sending packets to multiple receivers over different channels during a particular transmission window.
The Institute of Electrical Engineers (IEEE) 802.11 standard denotes a set of Wireless Local Area Network (WLAN) air interface standards developed by the IEEE 802.11 committee for short-range communications (e.g., tens of meters to a few hundred meters). In conventional IEEE 802.11 communications, a Media Access Control (MAC) Protocol Data Unit (MPDU) may be used to exchange messages/data between entities at the MAC layer of a protocol stack via a packet-switched network. One or more MPDUs may be encapsulated within a PHY Protocol Data Unit (PPDU) that is transmitted at the PHY layer of a protocol stack. For instance, the maximum number of MPDUs per PPDU may be eight (8). During transmission, some MPDU packets may be lost or corrupted. Consequently, a transmission scheme is implemented to resend lost MPDU packets. However, in MIMO communications, the retransmission scheme can lead to inefficiencies beyond just retransmitting an erroneous packet.
Therefore, there is a need for improved efficiency in MIMO communications that include retransmission protocols.